This invention relates to an improved bushing for mounting shank tools, such as drills, boring bars, and the like, within the socket bore of standard machine tool turrets or tool holders.
Conventionally, elongated, shank-type cutting tools are mounted within socket bores formed in machine tool turrets or tool holders used in connection with machine tools. For example, an elongated drill or boring bar has a shank portion which is fitted, coaxially within an elongated socket bore and is clamped within the socket by means of transversely arranged set screws or similar mechanical fasteners. Since the types of cutting tool may vary and their dimensions may vary, depending upon the particular machining job involved, tubular bushings are commonly used for holding the tool within the socket.
Conventional mounting bushings generally are formed of elongated tubes having exterior diameters, that are sized to closely fit within the sockets of a particular machine tool, and varying interior diameters which are sized to receive different size cutting tools. The bushings may be split, that is, slit along their lengths, so that they may be resiliently compressed by the usual set screws which extend transversely into the socket. Thus, with the split, resilient types of bushings, the shank of a cutting tool is frictionally gripped or clamped by the inward, resilient compression of the bushing due to the pressure of the set screws against the surface of the bushing. For that purpose, it is usual to provide a flat band-like area on the exterior of the bushing, against which the set screws or similar fasteners may engage.
In some types of bushings, holes may be formed in the walls thereof, so that the set screws or similar fasteners may extend transversely through the walls of the bushings and engage directly against the shanks of the cutting tools fitted within the bushings. Thus, the tools are directly clamped within the socket and the bushing is similarly held within the socket by means of the screws passing through the holes.
In any particular job-shop type of operation where the machine tools are used for different jobs, from time to time, and utilize different cutting tools, it is necessary to stock a large number of different bushings to accommodate the different size tools. In addition, since the locations of the set screw or screw fasteners in the sockets may vary from one type of machine tool to another, a collection of bushings must be maintained for each different machine tool. Consequently, it may be necessary for a particular shop to inventory a considerable number of bushings in order to provide the flexibility needed for different machining jobs.
This invention is concerned with an improved bushing which can be universally used, that is, used within different sockets whose fastening set screws may be differently located than the screws in the sockets of another machine tool. Consequently, the number of bushings needed in stock may be substantially reduced.